


Heated Bones

by GudufuFruit



Category: Undertale (Video Game)
Genre: I AM SO EXCITED TO USE IMAGES IN A FANFICTION!!! THANK YOU ZWAGYYYYYYY!!!, M/M, Size Difference, cumflation, kustard - Freeform, sleep fuck, sum fucc, sum good fucc, undertale - Freeform
Language: English
Status: Completed
Published: 2019-01-05
Updated: 2019-01-05
Packaged: 2019-10-04 13:21:01
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,158
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17305349
Author URL: https://archiveofourown.org/users/GudufuFruit/pseuds/GudufuFruit
Summary: Red is in heat and Sans needs to help him out.https://twitter.com/zwagyzins/status/1080722611393286150^^^^^ The source and who I wrote this for





	Heated Bones

**Author's Note:**

  * For [an amazing person~](https://archiveofourown.org/gifts?recipient=an+amazing+person%7E).



 

  
  


Red had swiped Sans in his arms the moment the other entered his room. The smaller skeleton was easily scooped up, a small amount of surprise on his face. But the scent filling the air, the look in his lover’s eyes-   
  
“Gimme a kiss, sweetheart.”   
  
Red had to be in heat. Sans’s surprise turned to excitement as he was all but smothered in a demanding kiss. He moaned into it, reaching up to grasp his lover’s coat. He gripped the fluff as Red began to move him towards the bed, literally carrying him over. As they moved Red began to grope over Sans’s shorts, causing his smaller lover to moan into their sweet kiss.    
  
Sans was placed on the bed, Red slipping on to tower over the much smaller skeleton. Sans ran his tongue over his teeth, shivering as Red continued to paw over his groin.    
  
“You uh.. Know you could’ve just said something, right? I might be a bit more prepa-o-ohgod…!”   
  
Sans covered his mouth with a hand when Red began to rub him through his pants. Those massive fingers were truly  _ sinful _ in how good they felt. Red chuckled and leaned down, running his tongue down Sans’s vertebrae. His tongue even went so far as to dip into the top of his lover’s ribcage, Sans shivering in bliss.    
  
“Y’know I couldn’ tell ya.”    
  
Red’s voice was low as he rumbled into Sans’s neck. He rubbed his face gently against his lover’s skull, rumbling in anticipation.    
  
“We both know you’d do somethin’ t’piss me off.”    
  
Sans gasped when he felt teeth run over his shoulder, a hand moving in to begin slipping his shorts down.    
  
“E-Easy with the tee-EEth!”   
  
Sans gripped his boyfriend’s jacket tighter when he was nibbled on, that warm tongue soothing away the mild pain. Red easily slipped his lover’s shorts off, moving a hand up to gently rub over his lover’s pelvis. The massive hand simply pet around Sans’s forming magic, toying and teasing the bone.    
  
“Y’know it’s hard f’me t’take it easy, right?”   
  
Sans nodded, watching as his lover sat back to tower over him. He took in a shivering breath, spreading himself more. His magic finally settled at seeing what Red had chosen for his heat. To be honest, Sans was a bit scared of the sheer size of his lover, even clothed, but it always felt incredible. He knew it wouldn’t hurt if Red prepared him.    
  
“You don’t have to.”    
  
Red chuckled at that, moving his hand down to rub a finger over Sans’s slit. Sans gasped when it slipped into him, one eye closing as he kept eye contact with his lover. Red was grinning down at him, a hand on the bed beside his lover to prop himself up. His tongue was sticking out as he breathed, just taking in the sight below himself.    
  


 

“Y’look beautiful like that. All spread’n needy…”   
  
Red rumbled lowly before moving back in to lock Sans in a kiss. He was stopped by a hand covering his mouth. He stared down at his lover, slowly moving his finger out. He narrowed his eyes as Sans struggled to form his thoughts, deciding to slip his tongue over the palm covering his mouth. He drew a few fingers in and Sans shivered, moaning when the other began to suck on them.    
  
“I said you don’t have to be ge-EEENtle-!”   
  
Sans’s body jolted when that finger rammed back into him, a sinister smirk forming around his fingers. Sans covered his mouth with a hand, Red easily taking it away. He pinned it to the bed and leaned over his lover, his finger moving at a nice, slow pace.    
  
“Y’really wan’ me t’break ya?”    
  
Sans gave a small nod, Red diving back into his neck. He yelped when he was given a particularly rough nip, though that tongue soothed it away. He went back to holding Red’s jacket, running his fingers through the fluff to get a nice hold. He shut his eyes when he felt Red swap fingers in him, knowing what was next.    
  
“I’d love t’break ya, but I like ya too much.”    
  
Sans scrunched his eyes shut as Red eased two fingers into him, his magic stretching wide to accommodate them. Red nuzzled into Sans’s neck, forcing his head to the side. He was beginning to lose control of himself but he needed to stay strong, just for a while longer.    
  
Red inhaled deeply, forcing himself to calm down. He breathed the warm air over his lover’s neck and went back to nibbling and licking, his fingers slowly beginning to move. Just a bit longer, spread him wide, then take him.    
  
“Ahhhnnn~”   
  
Sans closed his eyes as his lover worked, soon getting used to the stretch. Red could feel his lover relaxing beneath him and spread his fingers.    
  
“Red!”   
  
Sans arched his back as those fingers spread him wide, grip on his lover’s jacket tightening. He choked out a moan as Red chuckled into his neck, drinking in those sweet sounds. He slipped in a third finger and Sans saw white. Red waited for that look of pure bliss to slip from his lover’s face, a horrible smirk on his own.    
  
“Really?”   
  


Sans’s cheeks colored and he looked away, breathing hard. How was he supposed to keep it together when Red was doing all of that to him? He  _ loved _ the feeling of being stretched so wide, he shouldn’t be surprised Sans couldn’t keep it together.    
  
“Y’gonna cum again when I stick it in ya?”   
  
Sans shivered, giving Red a half lidded grin. He wiggled his hips, Red rolling his eyes. He pulled his fingers out, watching as a thin trail of magic followed after. He brought it to his mouth and ran his tongue through it, tasting his love. Sans swallowed thickly, wanting that tongue on and in him now.    
  
Red brought his fingers into his mouth, shifting to remove his own shorts. They were removed easily enough, his other hand finally slipping free once it was clean. He licked his teeth and brought a hand to his own cock.   
  
Sans watched as the other’s magic pulsed in time with his soul, letting out a soft sound. Red shut his eyes as he worked on himself, his mind starting to grow fuzzy. When something warm ran over his tip, he rumbled lowly in bliss, looking down. Sans peeped up at him, tongue running from his lover’s tip down to his base.    
  


Red put a hand on his lover’s skull, guiding him in his motions. Sans shut his eyes as he worked, wrapping his hands around the other’s massive magic. He tried to take the tip in his mouth, his teeth getting in the way. He laved his tongue over the tip, even poking it in the small slit on top. Red grit his teeth, his hand tightening ever so slightly on his lover’s skull.    
  
Sans peeped an eye open, licking teasingly just beneath Red’s tip. That was the final straw.    
  
Red grabbed Sans by the shoulders and turned him around, pulling him against his own chest. He flopped forward on the bed, pinning his lover down as he positioned himself, burying his face in Sans’s shoulder. Sans moaned into the sudden shift, spreading his legs as best he could. He could feel his lover positioning himself and braced himself.    
  
Red’s tongue lolled out as he finally pushed into his love. He let out a low moan, not stopping until he was fully seated in that tight magic. Sans had buried his face in his arms, biting into the fabric of his jacket. He shut his eyes when Red began to pull back out, thrusting back in when he was half out. Sans was shoved across the bed, biting harder into his jacket as the pleasure mixed in with the sweet pain of being pushed to his limits. 

 

“God, y’feel so good, babe.”   
  
Red rumbled lowly as he pulled back out, shutting his eyes. He nuzzled into his lover’s shoulder before biting into it and ramming back inside. Sans  _ screamed _ as bliss shot through his very core, body shoved hard forward on the bed. Red’s arm beneath him kept him from going too far, pulling him back for another harsh slam. Before long tears were streaming down his face, head being shoved up and down on the bed. His hands gripped hard at the sheets, eyelights rolling back in his head as his tongue stuck out. He was the definition of bliss.    
  
Red had started growling with each thrust, muffling himself as best he could in his lover’s shoulder. He released him from his grip only to shift to the other side and latch on, moving for a new angle from behind. Sans was moaning with each thrust, praising Red as he kept going. He could feel the other getting rougher and rougher with him until all he saw was white.    
  
The shout beneath him had Red chasing his own climax, leaning back to sit. He grabbed his lover’s shoulders and middle, easily forcing him up and down until he finally had his first release. 

 

 

His tongue slipped out as he panted with an open mouth, bliss written all over his face. Sans’s blissed out expression turned to furrowed brows, his body trembling as he was filled with his lover’s cum. His magic felt as if it were being stretched past breaking, warmth slipping out around his lover’s magic. He could even feel some starting to slip to his knees, slowly dripping and pooling up beneath them. He shakily gripped for his lover’s arm, the other moving to his knee for some sort of ground. 

  


 

A warm tongue running over the back of his skull had Sans giving a soft whine. He tried to shift but Red held him firm, pausing from his grooming. 

 

“Still going, love…”    
  
He moved down to nuzzle into his lover’s skull.    
  
“Hold still f’me.”   
  
Sans felt as if he were going to burst, his eyes shut as he breathed shakily through his mouth.    
  
“Red… so full~...!”   
  
Red chuckled down into his neck, melting into his lover’s hood. He started to breathe more evenly as his bliss faded. His soul still felt too warm and Sans had stopped squirming beneath him. He nuzzled into his lover’s cheek before shifting the other off. Sans moaned as the pressure finally left him, making a horrible mess on the bed. He was put on all fours again, his lover moving in to lick over the back of his skull and down his neck.    
  
“Y’think y’can handle another?”   
  
Sans moaned in response, moving his hips up as best he could. Red licked over his cheek and moved back in position, easing inside his lover. Sans gripped the sheets, sighing out in bliss as Red began a much gentler pace this time. He was oversensitive and appreciated the change in pace.    
  
“A-ahh god, Red…!”   
  
Red nuzzled into Sans’s cheek before biting into his shoulder again, starting to pick up his pace. Sans could feel himself start to slip as his lover picked up, his moans picking up in volume again. Before long Red was back to slamming into him, ripping screams of bliss from his lover’s throat. He growled when he felt Sans get unbearably tight, slamming hard into that too tight hole.    
  
When he came a second time, he collapsed beside Sans, pulling him down hard. His lover had gone limp after his own climax, sleep having forcibly claimed him. Red breathed hard around his lover’s shoulder, soft growls slipping from him with every other huff. He wanted to keep going, he  _ needed _ to keep going, but Sans was  _ asleep _ !    
  
He whined into his lover’s neck, licking over his cheek and pulling him even closer.    
  
“Please… wake up…”   
  
Red breathed lowly into his lover’s neck, as if begging him would bring him back. He nuzzled hard into Sans’s side as his hips started moving again. He couldn’t stop himself. He continued to rut into his lover, shutting his eyes as he rocked his hips. Sans would forgive him.    
  
____   
  
By the time Sans was able to pull himself from sleep, his body was aching. His shoulders felt like knives had been stabbed into them. Dull knives, really dull and toothy kind. He groaned, shifting against the massive wall of warmth behind himself. He gasped at feeling his lover’s cock still inside himself. He shivered and looked down, able to see their magics mingling together. He looked up and gave a soft smile at seeing Red fast asleep, his tongue sticking out just the tiniest bit.    
  
Sans shut his eyes and relaxed into that warm embrace. Red was going to need more help with his heat later on, so it was best to get as much rest as he could. Or was that just an excuse for being lazy? Whatever it was, he was more than happy to fall back asleep in his lover’s arms. 


End file.
